“Irradiating monkeys would be one giant leap backward for NASA,” the group’s director of research policy Hope Ferdowsian said in a statement. “The proposed experiments are cruel, unnecessary, and lack scientific merit. There are better, more humane ways of understanding the potential dangers of interplanetary travel to humans. Scientific progress can only proceed with a strong ethical foundation.”

The petition claims that the research violates several mandates of the agency’s “Principles for the Ethical Care and Use of Animals” report.

“Genetic, physiological, and anatomical differences between humans and monkeys dramatically limit the conclusions that can be drawn from the planned experiments,” the petition states.

“Ongoing studies, including those funded by NASA and the U.S. Department of Energy, already use nonanimal methods to determine the effects of low-dose radiation on human tissues,” Ferdowsian wrote.

The group also questions the need for this type of research, claiming that “Interplanetary human travel is, at best, a highly speculative aim for the foreseeable future. It is obviously fraught with many dangers and enormous expense, while serving goals that are not at all clear. To put animals through radiation tests now in anticipation of such an enterprise is in no way justified.”